UNIVERSITY    OF    CALIFORNIA     AGRICULTURAL    EXPERIMENT   STATION 

~~.    .    -~-      ~-      .__._...   «■■«.-  BENJ.     IDE     WHEELER,     PRESIDENT 

COLLEGE   OF  AGR  CULTURE 

"va",~v-  THOMAS    FORSYTH    HUNT,    DEAN  AND   DIRECTOR 

BERKELEY  h.  e.  van  norman,  vice-director  and  dean 

University  Farm  School 


CIRCULAR  No.  197 
April,  1918 

SUGGESTIONS  FOR  INCREASING  EGG 

PRODUCTION  IN  A  TIME  OF 

HIGH  FEED  PRICES 

YELLOW  COLOR  AS  AN  INDICATION  OF 
EGG  PRODUCTION 

By  J.  E.  DOUGHERTY 


Increased  egg  production  per  hen  per  year  should  offset  increased 
cost  of  feed  and  will  decrease  the  cost  of  producing  eggs.  If  feed 
should  cost  $3.00  per  100  lbs.  and  a  laying  hen  should  eat  72  lbs.  of 
feed  a  year,  it  would  take  77  eggs  at  an  average  price  of  34  cents  per 
dozen  to  pay  her  feed  bill ;  whereas  with  feed  costing  $2.00  per  100  lbs. 
and  eggs  selling  at  an  average  annual  price  of  27  cents  per  dozen 
(average  price  in  1916),  only  64  eggs  would  be  required  to  pay  the 
yearly  feed  cost  per  hen.  Data  recently  compiled  indicate  that  the  cost 
of  feed  represents  approximately  70  per  cent  of  the  total  expense  per 
hen  on  a  typical  commercial  poultry  farm  in  California  where  no  feed 
but  green  stuff  is  grown.  On  this  basis  only  92  eggs  would  be  required 
to  pay  all  expenses  per  hen  if  feed  cost  $2.00  per  100  lbs.  and  eggs 
netted  the  producer  an  average  annual  price  of  27  cents.  With  feed 
costing  $3.00  per  100  lbs.  and  eggs  netting  34  cents,  however,  109  eggs 
must  be  laid  per  hen  per  year  to  meet  all  expenses. 

It  is  evident  that  as  feed  prices  rise,  the  average  yearly  egg  yield 
of  the  flock  must  be  increased  materially  if  profitable  returns  are  to 
continue.  To  secure  this  necessary  increase  in  the  production  of  the 
flock,  immediate,  continued,  and  rigid  culling  becomes  imperative. 

Although  trapnesting  and  scientific  breeding  are  much  more 
reliable  and  far-reaching  in  results  than  any  method  or  methods  of 
judging  the  productive  abilities  of  fowls  by  means  of  physical  char- 


acteristics,  such  as  conformation,  color  of  shanks,  etc.,  which  are  either 
readily  visible  or  can  be  determined  by  handling,  the  latter  means 
have  been  shown  by  careful  and  rather  extended  tests  to  be  fairly 
accurate  and  therefore  of  material  aid  both  in  culling  low  producers, 
which  do  not  lay  enough  to  be  profitable,  and  in  indicating  the  better 
producers.  The  percentage  of  errors  is  sufficiently  small  to  make  the 
intelligent  use  of  such  observational  methods  of  judging  of  consider- 
able value  in  improving  the  average  productiveness  of  both  commercial 
and  farm  flocks  of  fowls  used  for  the  production  of  table  eggs  and 
from  which  the  increased  productive  results,  possible  by  a  more  ac- 
curate culling  out  of  the  poor  layers  on  the  basis  of  trapnest  records 
would  not  pay  for  the  added  expense  of  such  trapnesting. 

The  culling  out  of  the  unprofitable  layers  will  increase  the  average 
productiveness  of  the  flock  and  lower  the  feed  bill.  The  use  of  the 
better  layers  as  breeding  stock  will  aid  in  building  up  the  laying 
qualities  of  the  offspring,  especially  if  the  males  out  of  high-producing 
females  are  mated  to  these  better  layers. 

CONSTITUTION 

Constitution,  vitality,  and  health  are  fundamental  requirements  for 
heavy  egg  production.  Fowls  with  weak  constitutions  cannot  be 
expected  to  lay  well. 

The  constitutionally  strong  fowl  should  have  a  healthy,  well- 
groomed  appearance  and  clean-cut  action.  The  head  should  be  well 
proportioned,  the  beak  short  and  blunt,  eyes  round,  full  and  bright, 
comb  of  good  normal  size  for  the  variety,  well  carried  on  head,  of 
rather  fine  texture  and  with  a  rich  red  color.  A  long,  thin  beak,  dull, 
snaky  eye,  pale,  anaemic  comb,  and  spindle-legged,  gangling  body  do 
not  exist  on  the  constitutionally  vigorous  fowl. 

The  kernel  of  the  whole  question  of  vigor  is  that  the  heavy  laying 
fowl  must  be  a  well-built,  hardy,  active  bird  with  sufficient  stamina  to 
withstand  the  strain  of  abundant  egg  production. 


YELLOW  COLOR  AS  AN  INDICATOR  OF  EGG-LAYING  ABILITY 

In  all  yellow-legged  varieties  of  fowls,  the  yellow  coloring  pigment 
in  shanks,  beak,  ear-lobes  and  skin  (especially  noticeable  at  vent) 
appears  to  be  drawn  from  the  surface  of  the  body  as  the  number  of 
eggs  laid  increases  during  each  laying  season.  During  the  molting 
period  in  the  fall,  when  fewest  eggs  are  laid,  the  amount  of  yellow 


color  pigment  in  shanks,  etc.,  appears  to  increase  and  to  coach  a 
maximum  at  about  the  close  of  the  molt;  as  egg-production  increases 
during  the  following  spring  and  summer  those  hens  that  lay  the  most 
eggs  apparently  draw  more  of  the  yellow  pigment  from  the  surface  of 
the  shanks,  beak,  etc.,  than  do  hens  laying  fewer  eggs.  Therefore,  the 
comparative  shades  of  yellowness  of  the  shanks,  beak,  ear-lobes,  and 
skin  around  vent  in  different  fowls  would  seem  to  be  a  fairly  accurate 
indication,  in  late  spring,  during  summer,  and  until  the  beginning  of 
the  molt,  of  the  relative  productive  abilities  of  the  fowls  in  any  one 
flock  where  they  are  all  subject  to  the  same  feeding  conditions.  It  is 
possible  that  the  amounts  fed  (if  any)  of  feed-stuffs,  such  as  yellow 
corn,  which  contain  considerable  yellow  pigment,  might  affect  the  rate 
of  loss  of  yellow  from  shanks,  beak,  ear-lobes,  and  vent  of  birds  in 
different  flocks.  For  this  reason  it  would  seem  advisable  to  make 
yellow- color  comparisons  only  of  birds  in  the  same  flock  or  known  to 
be  fed  the  same  or  similar  rations. 

The  following  tables,  which  were  compiled  from  observations  made 
during  the  spring  and  summer  of  1917  upon  trapnested  S.  C.  White 
Leghorns  of  different  ages  just  as  they  would  be  found  in  a  typical 
flock,  show  in  detail  how  yellow-color  observations  compare  wTith  actual 
trapnest  records.  The  trapnest  records  are  for  the  year  ending  August 
31,  1917,  which  represents  about  the  normal  laying  year  from  molt  to 
molt.  "While  these  tables  indicate  considerable  inaccuracy  in  the  color 
observations  as  compared  with  actual  trapnest  performance,  especially 
as  regards  the  medium  and  poor  layers,  the  general  trend  of  the  results 
secured  is  such,  as  to  warrant  a  reasonable  measure  of  dependence  on 
such  observations  in  culling  and  grading  for  egg  production. 

A  study  of  table  1  would  indicate  that  May  is  perhaps  somewhat 
early  and  September  a  little  late  to  secure  best  results  from  the  use 
of  yellow-color  indications  for  culling.  This  is  probably  due  to  the 
fact  that  the  fowls  do  not  lay  enough  eggs  before  June  to  affect 
sufficiently  the  yellowness  of  their  shanks,  beak,  and  vent,  and  by 
September,  many  of  the  poorer  layers  whose  production  approaches 
the  line  of  separation  between  the  culls  and  the  profit-earning  hens, 
have  already  begun  to  slow  down  rapidly  in  their  laying.  The  average 
production  of  the  pale  birds,  however,  is  so  uniformly  high  in  the 
June,  July,  and  September  observations  as  to  show  that  the  better 
layers  may  be  picked  out  with  considerable  accuracy  during  these 
months. 


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No.  of  Hens 

Average  Eggs  per  year 

1,273 

157.7 

139 

129.5 

TABLE  2 

Summary  of  all  Shank  Color  Observations  made  during  Summer  of  1917 
(Taken  from  Table  1) 

Shade  of  Yellow  No.  of  Hens  Average  Eggs  per  year 

Pale  1,161                             156.1 

Medium  282                              139 

Yellow  162                             123.8 


TABLE  3 

Summary  op  all  Vent  Color  Observations  made  in  Summer  of  1917 
(Taken  from  Table  1) 
Shade  of  Yellow 

Pale 

Medium 

Yellow  109  129.1 


TABLE  4 

Summary  of  all  Beak  Color  Observations  made  in  Summer  of  1917 
(Taken  from  Table  1) 

Shade  of  Yellow  No.  of  Hens  Average  Eggs  per  year 
Pale                                  761  160 

Medium  200  145.5 

Yellow  190  126.3 

The  data  presented  in  tables  2  to  6  indicate  that  shank  color  and 
beak  color  are  somewhat  more  reliable  to  use  for  summer  culling  and 
grading  than  vent  color.  This  is  perhaps  due  to  the  fact  that  the 
yellow  pigment  leaves  and  returns  to  the  vent  more  rapidly  than  it 
does  to  shanks  and  beak.  The  Connecticut  Agricultural  Experiment 
Station  found  that  the  average  length  of  time  required  for  a  bird's 
vent  to  become  yellow  after  it  had  stopped  laying  was  fourteen  days, 
whereas  for  shanks  and  beak  a  much  longer  time  was  necessary.1 


TABLE  5 

Summary  of  all  Shank  and  Vent  Color  Observations  made  in  Summer  of  1917 

(Taken  from  Table  1) 


Shade  of  Yellow 

No.  of  Hens 

Average  Eggs 

Pale 

1,232 

158.8 

Medium 

76 

142.8 

Yellow 

92 

138.6 

i  A  Further  Investigation  of  Selection  of  High-producing  Tiers.  D.  E.  War- 
ner, Journal  of  American  Ass  'n  of  Instructors  and  Investigators  in  Poultry 
Husbandry,  Vol.  3,  No.  1  (Oct.,  1916),  p.  45. 


TABLE  6 

Summary  of  all  Shank  and  Beak  Color  Observations  made  in  Summer  of  1917 

(Taken  from  Table  1 ) 

Shade  of  Yellow  No.  of  Hens  Average  Eggs  per  year 

Pale  1,051  159.8 

Medium  135  133.4 

Yellow  129  124.6 

TABLE  7 

Summary  of  all  Color  Observations  made  on  Shanks,  Beak,  and  Vent 
during  Summer  of  1917 

Shade  of  Yellow  No.  of  Hens  Average  Eggs  per  year 

Pale  5,848                              158.2 

Medium  859                              137.0 

Yellow  690                              128.4 

Table  7  gives  the  summarized  results  secured  by  combining  all 
observations  included  in  tables  2  to  6.  The  average  results  thus  secured 
further  check  the  quite  consistent  trend  of  the  previous  tables  in 
pointing  out  the  utilitarian  value  of  differences  in  the  brightness  of 
yellow  color  in  shanks,  beak,  and  vent  of  yellow-legged  breeds  of  fowls 
as  an  aid  in  selecting  high  layers  and  in  culling  out  poor  layers. 

Although  the  investigation  reported  here  was  carried  on  with 
S.  C.  White  Leghorns,  similar  work  done  at  other  stations  with 
Plymouth  Rocks,  Wyandottes,  and  Rhode  Island  Reds  indicates  that 
the  results  of  this  investigation  will  apply  to  any  distinctly  yellow- 
legged  breed. 

STTMMAEY 

Increased  egg  production  will  offset  increased  cost  of  feed. 

Health  and  vigor  are  fundamental  to  high  egg  production. 

A  more  efficient  culling  of  the  low-producing  hens  and  the  use  of 
the  better  layers  mated  to  males  out  of  superior  layers  for  breeding 
will  build  up  the  average  productiveness  of  the  flock. 

The  yellowness  of  vent,  beak,  and  shanks  of  yellow-legged  breeds  is 
a  fairly  accurate  guide  to  the  laying  abilities  of  different  fowls  in  the 
same  flock. 

The  amount  of  yellow  coloring  materials  contained  in  the  ration 
fed  may  affect  the  rate  of  change  from  yellow  to  paleness,  and  vice 
versa,  in  different  flocks  or  even  in  different  pens  of  fowls. 

Yellow-color  indications  would  seem  to  be  of  the  most  value  during 
June,  July,  and  August.  Such  indications  should  apply  to  all  dis- 
tinctly yellow-legged  breeds. 


BIBLIOGRAPHY 

Correlation  between  egg-laying  activity  and  yellow  pigment  in  the  domestic 
fowl.  A.  F.  Blakeslee  and  D.  E.  Warner.  Science,  N.S.  41  (1915),  No.  1055, 
pp.  432-34. 

Method  of  selecting  the  high-producing  hens.  B.  O.  Kent.  Cornell  Country- 
man, 12  (1915),  No.  6,  pp.  481-84. 

External  characters  as  indications  of  egg  production.  B.  O.  Kent.  Journal 
of  American  Assoc,  of  Instructors  and  Investigators  in  Poultry  Flusb.,  Vol.  2, 
No.  8  (May,  1916),  pp.  63-64. 

A  further  investigation  of  selection  of  high-producing  hens.  D.  E.  Warner. 
Journal  of  American  Assoc,  of  Instructors  and  Investigators  in  Poultry  Husb., 
Vol.  3,  No.  1  (Oct.,  1916),  p.  4. 

The  histological  basis  of  shank  color  in  the  domestic  fowl.  H.  R.  Barrows. 
Me.  Agr.  Exp.  Sta.  Bull.  232,  pp.  237-52. 

Correlation  between  egg-laying  and  yellow  pigment  in  the  domestic  fowl. 
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Sudan  III  deposited  in  the  egg  and  transmitted  to  the  chick.  S.  II.  Gage 
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The  behavior  of  fat-soluble  dyes  and  stained  fat  in  the  animal  organism. 
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Xanthophyll,  the  principal  natural  yellow  pigment  of  the  egg  yolk,  body 
fat,  and  blood  serum  of  the  hen.  The  physiological  relation  of  the  pigment  to 
the  xanthophyll  of  the  plant.  L.  S.  Palmer.  Jour.  Biol.  Chem.,  23  (1915),  pp. 
261-79. 

Studies  with  Sudan  III  in  metabolism  and  inheritance.  O.  Riddle.  Jour. 
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Feeding  color — an  aid  in  studying  physiological  development.  C.  A.  Rogers. 
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Prolific  layers  and  how  to  select  them.  D.  E.  Warner.  Field,  26  (1916), 
pp.  24-25. 

The  correlation  between  body  pigmentation  and  egg  production  i  n  the 
domestic  fowl.  J.  Arthur  Harris,  A.  F.  Blakeslee,  and  D.  E.  Warner.  Genetics, 
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The  correlation  between  egg  production  during  various  periods  of  the  year 
in  the  domestic  fowl.  J.  A.  Harris  and  A.  F.  Blakeslee.  Genetics,  Vol.  3,  No.  1 
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STATION  PUBLICATIONS  AVAILABLE  FOR  FREE  DISTRIBUTION 


1897.  Resistant  Vines,  their  Selection,   Adaptation,   and   Grafting.      Appendix  to  Viticultural 
Report  for  1896. 

1902.  Report  of  the  Agricultural  Experiment  Station  for   1898-1901. 

1903.  Report  of  the  Agricultural   Experiment  Station  for   1901-03. 

1904.  Twenty-second  Report  of  the  Agricultural  Experiment  Station  for  1903-04. 

1914.  Report  of  the  College  of  Agriculture  and  the  Agricultural  Experiment  Station. 

1915.  Report  of  the  College  of  Agriculture  and  the  Agricultural  Experiment   Station. 

1916.  Report  of  the  College  of  Agriculture  and  the  Agricultural  Experiment  Station. 

1917.  Report  of  the  College  of  Agriculture  and  the  Agricultural  Experiment  Station. 

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242. 
246. 
248. 

250. 
251. 


252. 
253. 

255. 
257. 
261. 

262. 

263. 
264. 
265. 
266. 

267. 

268. 
270. 


No. 
113. 
114. 
115. 
121. 

124. 

126. 
127. 
128. 
129. 
131. 
133. 
135. 
136. 
137. 
138. 
139. 


140. 


142. 

143. 

144. 
147. 
148. 
150. 
151. 
152. 

153. 

154. 


155. 
156. 
157. 
158. 


Enological  Investigations.  271. 

Vine  Pruning  in  California,  Part  I.  272. 

Humus  in  California  Soils.  273. 

Vine  Pruning  in  California,  Part  II. 

The  Economic  Value  of  Pacific   Coast  274. 
Kelps. 

The  Loquat.  275. 

Utilization  of  the  Nitrogen  and  Organic 

Matter    in    Septic    and    Imhoff   Tank  276. 

Sludges.  277. 

Deterioration  of  Lumber.  278. 

Irrigation  and   Soil   Conditions   in  the  279. 

Sierra  Nevada  Foothills,  California.  280. 

The  Citricola  Scale. 

New  Dosage  Tables.  282. 

Melaxuma    of    the    Walnut,     "Juglans 

regia."  283. 

Citrus   Diseases   of   Florida   and   Cuba  284. 

Compared  with  Those  of  California.  285. 

Size  Grades  for  Ripe  Olives.  286. 

The  Calibration  of  the  Leakage  Meter.  288. 

Cottony  Rot  of  Lemons  in   California. 

A  Spotting  of  Citrus  Fruits  Due  to  the  290. 
Action  of  Oil  Liberated  from  the  Rind. 

Experiments  with  Stocks  for  Citrus.  291. 

Growing  and  Grafting  Olive  Seedlings. 

A  Comparison  of  Annual  Cropping,  Bi- 
ennial Cropping,  and  Green  Manures 
on  the  Yield  of  Wheat. 

CIRCULARS 
No. 

Correspondence  Courses  in  Agriculture.  160. 

Increasing  the  Duty  of  Water.  161. 

Grafting  Vinifera  Vineyards.  162. 

Some    Things    the    Prospective    Settler 

Should   Know.  164. 

Alfalfa   Silage  for  Fattening  Steers.  165. 

Spraying  for  the  Grape  Leaf  Hopper. 

House  Fumigation.  166. 

Insecticide  Formulas.  167. 

The  Control  of  Citrus  Insects.  168. 

STjraviner  for  Control  of  Walnut  Aphis. 

County  Farm  Adviser.  169. 

Official  Tests  of  Dairy  Cows.  170. 

Melilotus  Indica. 

Wood  Decay  in  Orchard  Trees.  172. 

The  Silo  in  California  Agriculture.  174. 

The   Generation    of   Hydrocyanic    Acid  175. 
Gas  in  Fumigation  by  Portable  Ma- 
chines. 176. 

The  Practical  Application  of  Improved 

Methods  of  Fermentation  in  Califor-  177. 

nia  Wineries  during  1913  and  1914.  181. 

Practical  and  Inexpensive  Poultry  Ap- 
pliances. 182. 

Control    of    Grasshoppers    in    Imperial 

Valley.  183. 

Oidinm  or  Powderv  Mildew  of  the  Vine.  184. 

Tomato  Growing  in  California.  185. 

"Lungworms." 

Round  Worms  in  Poultry.  186. 

Feedinc  and  Management  of  Hoes.  187. 

Some  Observations  on  the  Bulk  Hand-  188. 

ling  of   Grain   in   California.  19°. 

Announcement  of  the  California  State  191. 

Dairv  Cow  Competition.    1916-18.  192. 

Irrigation   Practice   in   Growing   Small  193. 

Fruits  in  California.  196. 

Bovine  Tuberculosis.  197. 

How  to  Operate  an  Incubator. 

Control  of  the  Pear  Scab.  198. 

Home  and  Farm  Canning. 


Feeding  Dairy  Calves  in  California. 

Commercial  Fertilizers. 

Preliminary  Report  on  Kearney  Vine- 
yard Experimental  Drain. 

The  Common  Honey  Bee  as  an  Agent 
in  Prune  Pollination. 

The  Cultivation  of  Belladonna  in  Cali- 
fornia. 

The  Pomegranate. 

Sudan  Grass. 

Grain  Sorghums. 

Irrigation  of  Rice  in  California. 

Irrigation  of  Alfalfa  in  the  Sacramento 
Valley. 

Trials  with  California  Silage  Crops  for 
Dairy  Cows. 

The  Olive  Insects  of  California. 

Irrigation  of  Alfalfa  in  Imperial  Valley. 

The  Milch  Goat  in  California. 

Commercial  Fertilizers. 

Potash  from  Tule  and  the  Fertilizer 
Value  of  Certain  Marsh  Plants. 

The  June  Drop  of  Washington  Navel 
Oranges. 

The  Common  Honey  Bee  as  an  Agent 
in  Prune  Pollination.      (2nd  report.) 


Lettuce  Growing  in  California. 

Potatoes  in  California. 

White    Diarrhoea    and    Coccidiosis    of 

Chicks. 
Small  Fruit  Culture  in  California. 
Fundamentals    of    Sugar    Beets    under 

California   Conditions. 
The  County  Farm  Bureau. 
Feeding  Stuffs  of  Minor  Importance. 
Spraying  for  the  Control  of  Wild  Morn- 

ing-Glory  within  the  Fog  Belt. 
The  1918  Grain  Crop. 
Fertilizing     California     Soils     for     the 

1918  Crop. 
Wheat  Culture. 
Farm  Drainage  Methods. 
Progress  Report  on  the  Marketing  and 

Distribution  of  Milk. 
Hog      Cholera      Prevention      and     the 

Serum  Treatment. 
Grain   Sorghums. 
Control     of     the     California     Ground 

Squirrel. 
Extending  the  Area  of  Irrigated  Wheat 

in  California  for  1918. 
Infectious  Abortion  in  Cows. 
A  Flock  of  Sheep  on  the  Farm. 
Beekeeoing  for  the  Fruit-Grower   and 

Small  Rancher,  or  Amateur. 
Poultry  on  the  Farm. 
Utilizing  the  Sorghums. 
Lambing  Sheds. 

Agriculture  Clubs  in  California. 
Pruning:  the  Seedless  Grapes. 
Cotton  in  the  San  Joaquin  Valley. 
A  Study  of  Farm  Labor  in  California. 
Dairy  Calves  for  Veal. 
Suggestions    for    Increasing    Egg    Pro- 
duction in  a  Time  of  High-Feed  Prices. 
Syrup  from  Sweet  Sorghum. 


